22,030 research outputs found
How to remove the boundary in CFT - an operator algebraic procedure
The relation between two-dimensional conformal quantum field theories with
and without a timelike boundary is explored.Comment: 18 pages, 2 figures. v2: more precise title, reference correcte
On local boundary CFT and non-local CFT on the boundary
The holographic relation between local boundary conformal quantum field
theories (BCFT) and their non-local boundary restrictions is reviewed, and
non-vacuum BCFT's, whose existence was conjectured previously, are constructed.Comment: 16 pages. Contribution to "Rigorous Quantum Field Theory", Symposium
in honour of J. Bros, Paris, July 2004. Based on joint work math-ph/0405067
with R. Long
Thermal States in Conformal QFT. II
We continue the analysis of the set of locally normal KMS states w.r.t. the
translation group for a local conformal net A of von Neumann algebras on the
real line. In the first part we have proved the uniqueness of KMS state on
every completely rational net. In this second part, we exhibit several
(non-rational) conformal nets which admit continuously many primary KMS states.
We give a complete classification of the KMS states on the U(1)-current net and
on the Virasoro net Vir_1 with the central charge c=1, whilst for the Virasoro
net Vir_c with c>1 we exhibit a (possibly incomplete) list of continuously many
primary KMS states. To this end, we provide a variation of the
Araki-Haag-Kastler-Takesaki theorem within the locally normal system framework:
if there is an inclusion of split nets A in B and A is the fixed point of B
w.r.t. a compact gauge group, then any locally normal, primary KMS state on A
extends to a locally normal, primary state on B, KMS w.r.t. a perturbed
translation. Concerning the non-local case, we show that the free Fermi model
admits a unique KMS state.Comment: 36 pages, no figure. Dedicated to Rudolf Haag on the occasion of his
90th birthday. The final version is available under Open Access. This paper
contains corrections to the Araki-Haag-Kaster-Takesaki theorem (and to a
proof of the same theorem in the book by Bratteli-Robinson). v3: a reference
correcte
Is Brazil really a catholic country? What opinions about abortion, sex between individuals who are not married to each other, and homosexuality say about the meaning of catholicism in three Brazilian cities
The idea of being a Catholic country is quite widespread throughout the nation. What does it mean to be Catholic in Brazil? Do Catholics follow the Catholic Doctrine? The objective of this paper is to investigate the relationship between religion and religious involvement (measured by religious affiliation and service attendance) and opinions about abortion, sex between individuals who are not married to each other, and homosexuality in São Paulo, Porto Alegre, and Recife. Data come from the survey “Spirit and Power: A 10-Country Survey of Pentecostals,” carried out in 2006. Results suggest that Brazilian Catholics are a very heterogeneous group with respect to opinions about abortion and sex between individuals who are not married to each other. In addition, service attendance among Catholics and those opinions are strongly correlated, except for the case of homosexuality, a topic which Catholics tend to have the same opinions about, irrespective of their religious involvement. Committed Protestants are, by far and away, the most conservative group.Brazil
Stability of Intercelular Exchange of Biochemical Substances Affected by Variability of Environmental Parameters
Communication between cells is realized by exchange of biochemical
substances. Due to internal organization of living systems and variability of
external parameters, the exchange is heavily influenced by perturbations of
various parameters at almost all stages of the process. Since communication is
one of essential processes for functioning of living systems it is of interest
to investigate conditions for its stability. Using previously developed
simplified model of bacterial communication in a form of coupled difference
logistic equations we investigate stability of exchange of signaling molecules
under variability of internal and external parameters.Comment: 11 pages, 3 figure
Radio emission from dark matter annihilation in the Large Magellanic Cloud
The Large Magellanic Cloud, at only 50 kpc away from us and known to be dark
matter dominated, is clearly an interesting place where to search for dark
matter annihilation signals. In this paper, we estimate the synchrotron
emission due to WIMP annihilation in the halo of the LMC at two radio
frequencies, 1.4 and 4.8 GHz, and compare it to the observed emission, in order
to impose constraints in the WIMP mass vs. annihilation cross section plane. We
use available Faraday rotation data from background sources to estimate the
magnitude of the magnetic field in different regions of the LMC's disc, where
we calculate the radio signal due to dark matter annihilation. We account for
the e+ e- energy losses due to synchrotron, Inverse Compton Scattering and
bremsstrahlung, using the observed hydrogen and dust temperature distribution
on the LMC to estimate their efficiency. The extensive use of observations,
allied with conservative choices adopted in all the steps of the calculation,
allow us to obtain very realistic constraints.Comment: 9 pages, 7 figure
Modular Structure and Duality in Conformal Quantum Field Theory
Making use of a recent result of Borchers, an algebraic version of the
Bisognano-Wichmann theorem is given for conformal quantum field theories, i.e.
the Tomita-Takesaki modular group associated with the von Neumann algebra of a
wedge region and the vacuum vector concides with the evolution given by the
rescaled pure Lorentz transformations preserving the wedge. A similar geometric
description is valid for the algebras associated with double cones. Moreover
essential duality holds on the Minkowski space , and Haag duality for double
cones holds provided the net of local algebras is extended to a pre-cosheaf on
the superworld , i.e. the universal covering of the Dirac-Weyl
compactification of . As a consequence a PCT symmetry exists for any
algebraic conformal field theory in even space-time dimension. Analogous
results hold for a Poincar\'e covariant theory provided the modular groups
corresponding to wedge algebras have the expected geometrical meaning and the
split property is satisfied. In particular the Poincar\'e representation is
unique in this case.Comment: 23 pages, plain TeX, TVM26-12-199
Desenvolvimento de biscoito tipo grissini com farinha do resíduo da pupunheira.
Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos
Algebraic conformal quantum field theory in perspective
Conformal quantum field theory is reviewed in the perspective of Axiomatic,
notably Algebraic QFT. This theory is particularly developped in two spacetime
dimensions, where many rigorous constructions are possible, as well as some
complete classifications. The structural insights, analytical methods and
constructive tools are expected to be useful also for four-dimensional QFT.Comment: Review paper, 40 pages. v2: minor changes and references added, so as
to match published versio
A New Approach to the Study of Stellar Populations in Early-Type Galaxies: K-band Spectral Indices and an Application to the Fornax Cluster
New measurements of K-band spectral features are presented for eleven
early-type galaxies in the nearby Fornax galaxy cluster. Based on these
measurements, the following conclusions have been reached: (1) in galaxies with
no signatures of a young stellar component, the K-band Na I index is highly
correlated with both the optical metallicity indicator [MgFe]' and central
velocity dispersion; (2) in the same galaxies, the K-band Fe features saturate
in galaxies with sigma > 150 km/s while Na I (and [MgFe]') continues to
increase; (3) [Si/Fe] (and possibly [Na/Fe]) is larger in all observed Fornax
galaxies than in Galactic open clusters with near-solar metallicity; (4) in
various near-IR diagnostic diagrams, galaxies with signatures of a young
stellar component (strong Hbeta, weak [MgFe]') are clearly separated from
galaxies with purely old stellar populations; furthermore, this separation is
consistent with the presence of an increased number of M-giant stars (most
likely to be thermally pulsating AGB stars); (5) the near-IR diagrams discussed
here seem as efficient for detecting putatively young stellar components in
early-type galaxies as the more commonly used age/metallicity diagnostic plots
using optical indices (e.g Hbeta vs. [MgFe]').Comment: 47 pages, 16 figures, ApJ accepte
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